242 Address of the President of the British Association. 



have ever yet combined to perfect ; and which the Dean of Ely — a 

 man worthy to praise the work — pronounced to be a rare combination 

 of mechanical, chemical, and mathematical skill and knowledge. Its 

 actual operations have been suspended by a cause not less honorable to 

 Lord Rosse in another character, than the conception and early pro- 

 gress of his great instrument were to him as a man of science. They 

 have been retarded, so far as he himself is concerned, by the more 

 immediate and, I will say, higher duties which, as a magistrate, as a 

 landowner, and as a Christian gentleman, he owed, and has been pav- 

 ing to his neighbors, his tenantry, and his country, during the late awful 

 visitation which has afflicted Ireland. Yet perhaps my noble friend 

 will permit me to say, that while we not only do not blame him— we 

 even praise him cordially for having devoted his time, his mind, and 

 his wealth to those claims which could not be postponed, since they 

 affected the lives of those who in God's providence surrounded him— 

 there were, and there are others, two at least in his own country, and 

 one his most illustrious friend, Dr. Robinson, (but I speak without any 

 communication on the subject from that great observer and greater 

 philosopher,) who might have carried on the series of observations 

 which this wonderful telescope alone can effect, and might thus have 

 secured for his own division of the empire, the discovery of the planet 

 Neptune. 



" The Catalogues of Lacaille and the Histoire Celeste are now be- 

 fore the world ; and with the Catalogue of our Association, constitute 

 a series of most important gifts conferred on astronomy. I have 

 already said that I will not presume to measure the relative merits of 

 two eminent individuals ; — it is as little within my power to measure 

 the value of such gifts to science. That value can be.duly appreciated 

 by none but the great masters of this, the greatest of the sciences : but 

 I may be permitted to add, that here, also, come into beneficial action 

 the powers and the uses of such an association, which, rising above the 

 mere calculations of pecuniary profit, provides for the few who only 

 are capable of extracting the just benefit from such works, those mate- 

 rials of advancing knowledge which are beyond the reach of individuals. 

 " The Astronomer Royal has done me the honor and the kindness, by 

 a paper which I have just received from him, to make me the vehicle 

 of communicating his wisdom to you on a most important and inter- 

 esting discovery of the past year. 



" » In the lunar theory a very important step has been made in 

 course of the past year. When near the beginning of the present cen- 

 tury, a considerable number of the Greenwich lunar observations were 

 reduced by Burg for the purpose of obtaining elements for the con- 

 struction of his Lunar Tables, and generally for the comparison of the 

 moon's observed place with Laplace's theory, it was found impossible 

 to reconcile the theoretical with the observed places except by the as- 

 sumption that some slowly varying error affected the epoch of the 

 moon's mean longitude. From the nature of the process by which the 

 errors of the elements are found, the conclusion upon the existence ,ot 

 this peculiar error is less subject to doubt than that upon any other 



So certain did it appear, that Laplace devoted to it one entire 

 r in the Mecanique Celeste, with the title ' On an inequality 01 



the 



error. 



